Hendrik Poinar: Bring back the woolly mammoth!

Translator: Joseph Geni Reviewer: Morton Bast

譯者: Shengwei Cai 審譯者: Anny Chung

When I was a young boy,

當我還小的時候

I used to gaze through the microscope of my father

常常透過父親房間裡的顯微鏡

at the insects in amber that he kept in the house.

觀察琥珀裡的昆蟲

And they were remarkably well preserved,

牠們保存得非常完好

morphologically just phenomenal.

其完好程度簡直令人驚奇

And we used to imagine that someday,

而且我們過去常想像

they would actually come to life

是不是有一天牠們會甦醒

and they would crawl out of the resin,

然後會從樹脂裡爬出來

and, if they could, they would fly away.

如果牠們能飛的話 牠們是不是會飛走

If you had asked me 10 years ago whether or not

如果十年前你問我

we would ever be able to sequence the genome of extinct animals,

我們能不能把滅絕動物的基因組排序

I would have told you, it's unlikely.

我會告訴你，不太可能

If you had asked whether or not we would actually be able

如果你問我們能不能

to revive an extinct species,

使滅絕的生物復活

I would have said, pipe dream.

我會說，做白日夢吧

But I'm actually standing here today, amazingly,

吃驚的是，今天我實實在在的站在這兒

to tell you that not only is the sequencing

告訴大家，絕種動物基因組排序是可能的

of extinct genomes a possibility, actually a modern-day reality,

事實上這已成為現實

but the revival of an extinct species is actually within reach,

復活滅絕動物的可能性已是能力所及

maybe not from the insects in amber --

但可能不是復活琥珀裡的昆蟲

in fact, this mosquito was actually used

- - 這隻蚊子曾是「侏羅紀公園」的靈感來源 - -

for the inspiration for "Jurassic Park" —

- - 這隻蚊子曾是「侏羅紀公園」的靈感來源 - -

but from woolly mammoths, the well preserved remains

而是通過凍土裡保存完好的殘骸

of woolly mammoths in the permafrost.

復活長毛象

Woollies are a particularly interesting,

長毛象是冰河時期特別有趣、特別典型的象徵

quintessential image of the Ice Age.

長毛像是冰河時期特別有趣、特別典型的象徵

They were large. They were hairy.

牠們體型巨大，身披長毛

They had large tusks, and we seem to have

有很大的長牙

a very deep connection with them, like we do with elephants.

我們好像和牠們關係密切 就像我們和大象一樣

Maybe it's because elephants share

可能因為大象和我們

many things in common with us.

有許多共同點

They bury their dead. They educate the next of kin.

比如埋葬死者，教育後代

They have social knits that are very close.

有很緊密的社交聯繫

Or maybe it's actually because we're bound by deep time,

或者可能因為我們在遠古時期就有聯繫

because elephants, like us, share their origins in Africa

因為大象和我們人類一樣

some seven million years ago,

七百多萬年前起源於非洲

and as habitats changed and environments changed,

隨著棲地和環境變化

we actually, like the elephants, migrated out

我們人類和大象一樣

into Europe and Asia.

遷移到歐洲和亞洲

So the first large mammoth that appears on the scene

遠古出現的第一種猛獁象是南方猛獁

is meridionalis, which was standing four meters tall

身高四米，體重約十噸

weighing about 10 tons, and was a woodland-adapted species

適宜在森林中生存

and spread from Western Europe clear across Central Asia,

分佈在西歐地區、中亞地區

across the Bering land bridge

並跨過白令陸橋

and into parts of North America.

到達北美部分地區

And then, again, as climate changed as it always does,

之後，隨著氣候再次變化

and new habitats opened up,

新棲地出現

we had the arrival of a steppe-adapted species

便有了適宜在草原生存的種類

called trogontherii in Central Asia

即中亞地區的草原猛獁

pushing meridionalis out into Western Europe.

牠們把南方猛獁排擠到了西歐地區

And the open grassland savannas of North America

北美廣大的稀樹大草原出現後

opened up, leading to the Columbian mammoth,

便有了哥倫比亞猛獁

a large, hairless species in North America.

牠們體型巨大，沒有長毛，分佈在北美

And it was really only about 500,000 years later

大約在五十萬年之後

that we had the arrival of the woolly,

我們非常喜愛和了解的長毛猛獁才出現

the one that we all know and love so much,

我們非常喜愛和了解的長毛猛獁才出現

spreading from an East Beringian point of origin

牠們由白令海峽分布至中亞區域

across Central Asia, again pushing the trogontherii

又把草原猛獁排擠到了中歐地區

out through Central Europe,

又把草原猛獁排擠到了中歐地區

and over hundreds of thousands of years

在數百萬年過程中

migrating back and forth across the Bering land bridge

牠們反覆在冰河時期

during times of glacial peaks

橫跨白令陸橋

and coming into direct contact

和生活在南方的哥倫比亞猛獁

with the Columbian relatives living in the south,

有了直接聯繫

and there they survive over hundreds of thousands of years

牠們在那兒生存了數百萬年

during traumatic climatic shifts.

忍受嚴峻的氣候突變

So there's a highly plastic animal dealing with great transitions

所以這種生存能力極強的動物

in temperature and environment, and doing very, very well.

對溫度和環境的劇烈轉變 適應得非常好

And there they survive on the mainland until about 10,000 years ago,

牠們在內陸生活直到一萬年前

and actually, surprisingly, on the small islands off of Siberia

出人意料的，約三千年前

and Alaska until about 3,000 years ago.

在西伯利亞外海的小島上 仍有它們的足跡

So Egyptians are building pyramids

當埃及人在建金字塔時

and woollies are still living on islands.

長毛象仍生活在海島上

And then they disappear.

之後牠們就消失了

Like 99 percent of all the animals that have once lived,

正如世界上 99% 動物一樣

they go extinct, likely due to a warming climate

牠們也滅絕了

and fast-encroaching dense forests

可能是由於氣溫升高

that are migrating north,

和迅速往北覆蓋的茂密的森林

and also, as the late, great Paul Martin once put it,

同樣可能是像已故保羅·馬丁曾說的那樣

probably Pleistocene overkill,

由於更新世時的人類獵殺

so the large game hunters that took them down.

所以是大型動物捕殺者讓牠們滅絕了

Fortunately, we find millions of their remains

我們幸運地發現了許多殘骸

strewn across the permafrost buried deep

深埋在西伯利亞和阿拉斯加的凍土中

in Siberia and Alaska, and we can actually go up there

我們可以到那些地方去

and actually take them out.

把它們挖出來

And the preservation is, again,

其保存完好程度

like those insects in [amber], phenomenal.

像琥珀裡的昆蟲一樣令人驚奇

So you have teeth, bones with blood

有牙齒，帶血的骨頭

which look like blood, you have hair,

至少看起來還像血 還有毛髮

and you have intact carcasses or heads

而且有完整的屍體和頭顱

which still have brains in them.

頭顱內仍有腦髓

So the preservation and the survival of DNA

其保存完好程度和 DNA 的存活

depends on many factors, and I have to admit,

取決於很多方面，而我必須承認

most of which we still don't quite understand,

其中仍有很多我們不理解

but depending upon when an organism dies

但當生物體死亡時

and how quickly he's buried, the depth of that burial,

其被埋葬的速度、深度

the constancy of the temperature of that burial environment,

埋葬環境的氣溫穩定度

will ultimately dictate how long DNA will survive

會從根本上決定 DNA

over geologically meaningful time frames.

在地質學時間範疇內 存活的時間長短

And it's probably surprising to many of you

可能會令在座各位感到意外的是

sitting in this room that it's not the time that matters,

其實埋葬年代並不重要

it's not the length of preservation,

保存時間長短也不重要

it's the consistency of the temperature of that preservation that matters most.

最重要的是保存環境的氣溫穩定性

So if we were to go deep now within the bones

如果我們深入研究

and the teeth that actually survived the fossilization process,

在石化過程中倖存的骨頭和牙齒

the DNA which was once intact, tightly wrapped

曾被組織蛋白緊緊包裹著的 DNA

around histone proteins, is now under attack

曾被組織蛋白緊緊包裹著的 DNA

by the bacteria that lived symbiotically with the mammoth

現在面臨猛獁體內的共生細菌攻擊

for years during its lifetime.

現在面臨猛獁體內的共生細菌攻擊

So those bacteria, along with the environmental bacteria,

所以這些細菌、環境中的細菌

free water and oxygen, actually break apart the DNA

游離水和氧氣把 DNA 分裂成細小碎片

into smaller and smaller and smaller DNA fragments,

游離水和氧氣把 DNA 分裂成細小碎片

until all you have are fragments that range

這些碎片裡最小的是10 鹼基對

from 10 base pairs to, in the best case scenarios,

在最好的情況下

a few hundred base pairs in length.

可能有長度為幾百鹼基對的碎片

So most fossils out there in the fossil record

所以化石記錄裡的大多數化石

are actually completely devoid of all organic signatures.

都完全缺乏有機特徵

But a few of them actually have DNA fragments

但仍有一些 DNA 碎片

that survive for thousands,

存活了上千年

even a few millions of years in time.

甚至上百萬年

And using state-of-the-art clean room technology,

通過最先進的無菌科技

we've devised ways that we can actually pull these DNAs

我們已經找出了幾種

away from all the rest of the gunk in there,

可以從殘骸中萃取出 DNA 的方法

and it's not surprising to any of you sitting in the room

而且，在座應沒有人會感到意外

that if I take a mammoth bone or a tooth

即使我能在猛獁象骨頭或牙齒裡

and I extract its DNA that I'll get mammoth DNA,

提取出猛獁象 DNA

but I'll also get all the bacteria that once lived with the mammoth,

也會隨之提取出所有和猛獁共生的細菌

and, more complicated, I'll get all the DNA

再麻煩的是，我還會提取出

that survived in that environment with it,

當時環境中所有存活下來的 DNA

so the bacteria, the fungi, and so on and so forth.

像是細菌、真菌等等

Not surprising then again that a mammoth

所以保存在凍土裡的猛獁象

preserved in the permafrost will have something

僅有 50% 屬於猛獁 DNA

on the order of 50 percent of its DNA being mammoth,

同樣不令人意外

whereas something like the Columbian mammoth,

而哥倫比亞猛獁

living in a temperature and buried in a temperate environment

生活及埋葬的環境屬溫帶氣候

over its laying-in will only have 3 to 10 percent endogenous.

這讓其 DNA 只有 3% 到 10% 的內生性

But we've come up with very clever ways

但我們已經找到一些巧妙的方法

that we can actually discriminate, capture and discriminate,

藉此我們可以捕捉和區分

the mammoth from the non-mammoth DNA,

猛獁 DNA 和非猛獁 DNA

and with the advances in high-throughput sequencing,

並經由最先進的高通量基因組測序技術

we can actually pull out and bioinformatically

提出這些猛獁 DNA 碎片

re-jig all these small mammoth fragments

利用生物資訊技術

and place them onto a backbone

將之重新排列於

of an Asian or African elephant chromosome.

亞洲象或非洲象的基因組骨幹上

And so by doing that, we can actually get all the little points

這樣我們就能得到

that discriminate between a mammoth and an Asian elephant,

所有區分猛獁象和亞洲象的基因變異

and what do we know, then, about a mammoth?

所以我們對猛獁象了解多少呢?

Well, the mammoth genome is almost at full completion,

猛獁象基因組快趨於完整了

and we know that it's actually really big. It's mammoth.

我們知道這個基因組非常巨大

So a hominid genome is about three billion base pairs,

原始人類的基因組大概有 30 億鹼基對

but an elephant and mammoth genome

但是大象或猛獁象的鹼基對

is about two billion base pairs larger, and most of that

比人類基因組多出 20 億鹼基對

is composed of small, repetitive DNAs

大多數是重複的短 DNA 片段

that make it very difficult to actually re-jig the entire structure of the genome.

因此重新排列這個基因組結構非常困難

So having this information allows us to answer

這些資訊讓我們能夠回答

one of the interesting relationship questions

一個跟猛獁象與其現代近親

between mammoths and their living relatives,

非洲象和亞洲象

the African and the Asian elephant,

有關的有趣問題了

all of which shared an ancestor seven million years ago,

七百萬年前，牠們有一個共同的祖先

but the genome of the mammoth shows it to share

但是猛獁的基因組顯示

a most recent common ancestor with Asian elephants

猛獁和亞洲象最近的共同祖先

about six million years ago,

是在六百萬年前

so slightly closer to the Asian elephant.

所以猛獁和亞洲象比較親近

With advances in ancient DNA technology,

拜近來純熟的古 DNA 技術之賜

we can actually now start to begin to sequence

我們現在可以開始排序

the genomes of those other extinct mammoth forms that I mentioned,

那些其他已滅絕猛獁的基因組

and I just wanted to talk about two of them,

我只想說其中兩種

the woolly and the Columbian mammoth,

長毛象和哥倫比亞猛獁

both of which were living very close to each other

這兩種猛獁在冰河時期生活得非常近

during glacial peaks,

這兩種猛獁在冰河時期生活得非常近

so when the glaciers were massive in North America,

當北美的冰河規模非常大時

the woollies were pushed into these subglacial ecotones,

長毛象被迫遷徙到冰河過渡帶

and came into contact with the relatives living to the south,

開始和生活在南方的親戚接觸

and there they shared refugia,

共同分享避難處

and a little bit more than the refugia, it turns out.

後來發現，牠們不只分享避難處

It looks like they were interbreeding.

牠們並與南方的猛瑪雜交

And that this is not an uncommon feature

這對長鼻目動物來說不稀奇

in Proboscideans, because it turns out

因為後來發現

that large savanna male elephants will outcompete

大型熱帶草原雄象在追求雌象時

the smaller forest elephants for their females.

會打敗體型較小的叢林象

So large, hairless Columbians

所以體型巨大且沒毛的哥倫比亞猛獁

outcompeting the smaller male woollies.

打敗了體型較小的雄性長毛象

It reminds me a bit of high school, unfortunately.

這讓我想起了我的高中生活

(Laughter)

（笑聲）

So this is not trivial, given the idea that we want

假如我們想要復活滅絕的物種

to revive extinct species, because it turns out

這就很重要了

that an African and an Asian elephant

因為亞洲象和非洲象

can actually interbreed and have live young,

能通過雜交繁衍後代

and this has actually occurred by accident in a zoo

1978 年在英國切斯特的一個動物園裡

in Chester, U.K., in 1978.

曾意外發生過這種事

So that means that we can actually take Asian elephant chromosomes,

這意味著我們可以用亞洲象染色體

modify them into all those positions we've actually now

並把它於我們發現的基因位置

been able to discriminate with the mammoth genome,

修改成猛獁基因組

we can put that into an enucleated cell,

然後放到無核細胞中

differentiate that into a stem cell,

讓它分化為幹細胞

subsequently differentiate that maybe into a sperm,

可能最後會分化為精子

artificially inseminate an Asian elephant egg,

再人工植入亞洲象卵子

and over a long and arduous procedure,

經過漫長艱苦的過程後

actually bring back something that looks like this.

就會產生一個這樣的動物

Now, this wouldn't be an exact replica,

這並不會是一個準確的複製長毛象

because the short DNA fragments that I told you about

因為我剛才提到的 DNA 重複片段

will prevent us from building the exact structure,

會妨礙我們創造一個精確的複製品

but it would make something that looked and felt

但是看起來和感覺起來

very much like a woolly mammoth did.

會很像一個真實的長毛象

Now, when I bring up this with my friends,

當我向朋友們討論這個的時候

we often talk about, well, where would you put it?

我們總談到，那你把牠放哪裡啊?

Where are you going to house a mammoth?

你會讓一頭猛獁象住哪裡?

There's no climates or habitats suitable.

根本沒有合適的氣候和棲地

Well, that's not actually the case.

其實並非如此

It turns out that there are swaths of habitat

因為在西伯利亞北部和育空地區

in the north of Siberia and Yukon

有足夠的合適棲地

that actually could house a mammoth.

能夠提供猛獁生活

Remember, this was a highly plastic animal

請記住，猛獁是適應力極強的動物

that lived over tremendous climate variation.

牠們經歷過驚人的氣候變化

So this landscape would be easily able to house it,

所以這片地區會很適宜牠們生活

and I have to admit that there [is] a part of the child in me,

我必須承認，我內心中的小男孩

the boy in me, that would love to see

我必須承認，我內心中的小男孩

these majestic creatures walk across the permafrost

渴望看到這偉大的生物

of the north once again, but I do have to admit

再次行走在北方的凍土上

that part of the adult in me sometimes wonders

但是我必須承認，成熟的我有時會想

whether or not we should.

我們到底是不是該把牠們復活

Thank you very much.

謝謝

(Applause)

（掌聲）

Ryan Phelan: Don't go away.

Ryan Phelan: 先別走

You've left us with a question.

你給我們留下了一個疑問

I'm sure everyone is asking this. When you say, "Should we?"

我保證大家都會問這個問題 當你說「該不該」時

it feels like you're reticent there,

我感覺你有所保留

and yet you've given us a vision of it being so possible.

但你已告訴我們復活猛獁的可能性

What's your reticence?

你在遲疑什麼?

Hendrik Poinar: I don't think it's reticence.

H. Poinar: 我不認為那是遲疑

I think it's just that we have to think very deeply

我覺得我們必須仔細考慮

about the implications, ramifications of our actions,

我們這個行為的後果和影響

and so as long as we have good, deep discussion

只要我們經過真誠深刻的討論之後

like we're having now, I think

就像我們現在這樣，我覺得

we can come to a very good solution as to why to do it.

我們就能找到一個解決方案

But I just want to make sure that we spend time

但是我只是想確定我們得先花時間

thinking about why we're doing it first.

考慮我們復活猛瑪的理由

RP: Perfect. Perfect answer. Thank you very much, Hendrik.

RP: 完美的答案 謝謝，Hendrik

HP: Thank you. (Applause)

HP: 謝謝 (掌聲)